Previous Knee Injury Research Articles

Prevalence of and Risk Factors for Total Hip and Knee Replacement in Retired National Football League Athletes

Background: Osteoarthritis is a substantial cause of disability. Joint replacement prevalence relates to the burden of severe osteoarthritis, and identifying risk factors for end-stage disease may indicate intervention opportunities. American football has high youth and elite participation, and determining risk factors for severe osteoarthritis may support future morbidity prevention. Purpose: To (1) determine the prevalence of hip and knee replacement in retired National Football League (NFL) athletes, (2) examine risk factors for replacement, and (3) identify the association between knee injuries and knee replacement. Study Design: Case-control study; Level of evidence, 3. Methods: Retired NFL athletes who participated in a general health survey were included. This historical cohort included those playing between 1929 and 2001. The association between self-reported playing or injury history, and replacement after retirement, was assessed with prevalence ratios (PRs). Models were adjusted for potential confounders of age and weight. Results: Data for 2432 retired male NFL players (69.3% response rate) who had participated in football for a mean 15.2 years were included, in which 277 players reported replacement after retirement (11.4%). More participants reported knee replacement (7.7%) than hip replacement (4.6%). The majority of participants reported previous severe knee injury (53%), and the most prevalent was meniscal tear (32.2%). In multivariable models, age (10-year increase, PR, 2.23; 95% CI, 1.99-2.51), current weight (PR, 1.10; 95% CI, 1.06-1.14), and reporting 1 (PR, 1.78; 95% CI, 1.14-2.77), 2 (PR, 1.91; 95% CI, 1.16-3.15), or ≥3 knee injuries (PR, 3.44; 95% CI, 2.33-5.09) were associated with knee replacement. Age (10-year increase, PR, 1.86; 95% CI, 1.59-2.18), linemen (PR, 1.62; 95% CI, 1.03-2.55), and reporting 1 (PR, 1.72; 95% CI, 1.05-2.80), 2 (PR, 2.77 95% CI, 1.58-4.84), or ≥3 (PR, 2.44; 95% CI, 1.52-3.91) hip injuries were associated with hip replacement. Each reported knee injury type was cross-sectionally associated with replacement after retirement (P < .05). Conclusion: Knee replacement was more prevalent than hip replacement. Risk factors differed between the hip and the knee, with age and severe joint injury associated with hip and knee replacement, weight with knee replacement, and playing position associated with hip replacement. Joint injury and weight management may be prevention opportunities to reduce morbidity and end-stage osteoarthritis in this population.

Partial Patella Tendon Tear in a Middle-Aged Man with No Previous Knee Injuries: A Non-Surgical Approach

Partial Patella Tendon Tear in a Middle-Aged Man with No Previous Knee Injuries: A Non-Surgical Approach

Every second retired elite female football player has MRI evidence of knee osteoarthritis before age 50years: a cross-sectional study of clinical and MRI outcomes.

To assess knee health in retired female football players, using magnetic resonance imaging (MRI) and self-report. The focus of analysis were degenerative changes of the tibiofemoral joint, and their relationship to osteoarthritis symptoms and previous knee injury. Forty-nine retired elite, female football players (98 knees) aged 37years on average participated. Tibiofemoral cartilage and meniscus status of both knees were evaluated using MRI and graded according to modified Outerbridge and Stoller classifications, respectively. Symptoms were assessed through a standardised questionnaire (Knee Osteoarthritis Outcome Score: KOOS). Knee injury history was recorded via a semi-structured interview. To investigate how injury variables relate to outcomes, binary logistic regression models were used and reported with odds ratios (OR). Fifty-one per cent of players (n = 25) fulfilled the MRI criterion for knee osteoarthritis, 69.4% (n = 34) had substantial meniscal loss and 59.6% (n = 28) reported substantial clinical symptoms. Chondral- and meniscal loss were associated with significantly lower scores on three of five KOOS subscales (p < .05). Both chondral and meniscal loss were significantly predicted by previous traumatic knee injury (OR = 4.6, OR = 2.6), the injury affecting the non-striking leg (OR = 8.6, OR = 10.6) and type of injury; participants with combined ACL/meniscus injuries had the highest risk for substantial chondral and meniscal loss (OR = 14.8, OR = 9.5). Chondral loss was significantly predicted by isolated meniscus injury treated with partial meniscectomy (OR = 5.4), but not by isolated reconstructed ACL injury. Clinical symptoms were only significantly predicted by previous traumatic knee injury (OR = 5.1). Serious degenerative changes were found in a high number of retired female football players' knees 10years after their career. Meniscal integrity is key for knee osteoarthritis outcomes in young adults, and thus, its preservation should be a priority.

Classification of gait muscle activation patterns according to knee injury history using a support vector machine approach

Abnormal muscle activation patterns during gait following knee injury that persist past the acute injury and rehabilitation phase (>three years) are not well characterized but may be related to post-traumatic knee osteoarthritis. The aim was to characterize the abnormal muscle activity from electromyograms of five leg muscles that were recorded during treadmill walking for young adults with and without a previous knee injury 3–12 years prior. The wavelet transformed and amplitude normalized electromyograms yielded intensity patterns that reflect the muscle activity of these muscles resolved in time and frequency. Patterns belonging to the affected or unaffected leg in previously injured participants and patterns belonging to a previously injured vs. uninjured participant were grouped and then classified using a principal component analysis followed by a support vector machine. A leave-one-out cross-validation was used to test the model significance and generalization. The results showed that trained classifiers could successfully recognize whether muscle activation patterns belonged to the affected or unaffected leg of previously injured individuals. Classification rates of 83% were obtained for all subjects, 100% for females only, indicating sex-specific knee injury effects. In contrast, it was not possible to discriminate between patterns belonging to the previously injured legs or dominant legs of control subjects. For females, the injured leg showed a stronger muscle activity for hamstring muscles and a lower activity for the vastus lateralis. In conclusion, systematic knee injury effects on the neuromuscular control of the knee during gait were present 3–12 years later.

Younger age and hamstring tendon graft are associated with higher IKDC 2000 and KOOS scores during the first year after ACL reconstruction.

Although reference values in healthy subjects have been published for both the International Knee Documentation Committee 2000 subjective knee form (IKDC 2000) and the Knee injury and Osteoarthritis Outcome Score (KOOS), data obtained during the first year after anterior cruciate ligament reconstruction (ACL-R) are sparse. The aim was to establish patient reference values for both questionnaires at different time points and depending on nine individual patient characteristics during the first year after ACL-R. Prospectively recorded data from a hospital-based registry were retrospectively extracted from the database. IKDC 2000 and KOOS questionnaires were self-administered pre-operatively and 6weeks, 3months, and 6 and 12months following primary ACL-R. Score values were compared according to nine individual patient criteria: gender, age, body mass index, level of activity, involvement in competition, previous contralateral knee injury and/or surgery, graft type, meniscal repair and/or cartilage lesions. The feature which had a significant and consistent impact on the outcomes was considered as main reference. Two-hundred and nighty-eight patients met the inclusion criteria. Overall, the score values increased over time after ACL-R. At 12months, they were significantly greater than at any other time point (p < 0.05). The main individual feature influencing the IKDC 2000 score was age. Patients below 30years of age had up to 9 points higher IKDC 2000 score values at all time points (p < 0.05). The main individual characteristic influencing the KOOS score was graft type. Patients with hamstring tendon grafts (STGR) had up to 15 points higher KOOS score values than patients with bone-patellar tendon-bone (BPTB) grafts during the first months after ACL-R (p < 0.05). At 12months, no differences in KOOS score values could be identified anymore. Younger age (< 30years) and STGR grafts were related to higher IKDC 2000 and KOOS score values within the first year after primary ACL-R. The patient reference values adjusted to age and graft provided in this study may help to identify patients with lower outcomes within the first year after ACL-R. Level III.

Evaluation kinaesthetic proprioceptive deficit after knee anterior cruciate ligament (ACL) reconstruction in athletes

PurposeThe objective of this study was to evaluate kinaesthetic proprioceptive deficit after knee anterior cruciate ligament (ACL) reconstruction in two populations of athletes, those in the post-surgery period and those in re-training during the intensive program-training phase.MethodsWe performed a prospective study in ACL-operated athletes without previous knee injuries, with 32 athletes in each group. Time since surgery in the operated athletes in the post-surgery group was 21 to 35 days, and between three and 9 months in the re-training group. We also analysed a control group of 32 uninjured non-operated subjects with a similar sporting level. Proprioception was evaluated using the threshold to detection of passive motion (TDPM) test with Biodex-type isokinetic equipment comparing operated knees, non-operated knees and control uninjured non-operated group. The control group was tested twice, 1 day apart to control reproducibility, using the intraclass correlation coefficient (ICC). The p-value threshold for statistical significance between different groups in hypothesis testing was <.05.ResultsTDPM reproducibility was excellent (right knee: ICC = 0.80, left knee: ICC =0.72). We found a bilateral kinaesthetic deficit in post-surgery patients compared to the control group (p < 0.001 and p = 0.011), which was significantly higher on the operated side (p = 0.001). Re-training patients had no significant difference between operated and uninjured knees, but had a kinaesthetic deficit on operated limbs (p = 0.036) compared to the control group.ConclusionThere was a bilateral deficit in post-surgery athletes with a significant difference between injured and healthy knees, which could be explained by a change in the central nervous system. Compared to the control group, a proprioceptive deficit was only seen for re-training patients on the operated side and not in the healthy limb. Kinaesthetic recovery may be faster for the uninjured side as initial deficit is lower.Level of evidence II.

Bilateral Quadriceps Strength Asymmetry Is Associated With Previous Knee Injury in Military Special Tactics Operators.

Eagle, SR, Keenan, KA, Connaboy, C, Wohleber, M, Simonson, A, and Nindl, BC. Bilateral quadriceps strength asymmetry is associated with previous knee injury in military special tactics operators. J Strength Cond Res 33(1): 89-94, 2019-Bilateral strength asymmetries have been related to lower-limb injury in athletes. Given that military populations often participate in recreational sport, in addition to a physically demanding workload, bilateral strength asymmetries may be related to injury in military populations. The purpose of this study was to determine whether isokinetic strength differs between Operators with/without self-reported knee injury (KI), and to examine the odds of displaying a lower-extremity strength asymmetry based on previous KI history. Operators (n = 150) self-reported injury history and performed isokinetic knee strength testing. Cohorts were separated by those who reported/not reported KI. Mean isokinetic knee strength and odds ratios, with subjects' KI history compared with strength differences: <10, 10-20, and >20%, were calculated. Operators who reported KI demonstrated larger bilateral knee extension (KE) strength differences compared with those who did not report an injury (injured: 13.5 ± 12.9% vs. noninjured: 8.1 ± 5.9%, p = 0.01). Operators with <10 or 10-20% KE strength difference had 76-77% reduced odds of previous KI, compared to those with >20% strength difference (p < 0.05). Operators with previous KI demonstrated bilateral differences in KE strength. Those with <10 or 10-20% strength differences had reduced odds of reporting previous KI. Strength and conditioning professionals should consider unilateral, targeted exercises in reducing bilateral asymmetry to rectify more balanced strength between limbs. Targeted exercise programs may improve bilateral strength differences and limit reinjury risk.

Contact times of change-of-direction manoeuvres are influenced by age and the type of sports: a novel protocol using the SpeedCourt® system.

Side-to-side asymmetry in side-cutting manoeuvres is a known risk factor for severe knee injury. Potential leg asymmetry during ground contact times of different change-of-direction manoeuvres was evaluated in athletes by means of the recently developed SpeedCourt® system. The hypotheses were that ground contact times and the limb symmetry index are affected by age and the type of sports. One-hundred and sixty-five athletes (149 men, 16 women, age 16.5 ± 5.1) of popular team sports such as football, team handball and baseball were assessed by means of three different tests [side-hop, lateral change-of-direction (COD) and diagonal COD] using the SpeedCourt® system. Analysis included the factors age, sex, type of sports, ground contact time, leg symmetry index and limb dominance. During lateral but not diagonal COD tests, football players had shorter contact times than players of team handball (p = 0.026) and baseball (p = 0.015) of the same age group. The side-hop tests yielded differences in the leg symmetry index between players < 16years and players > 16years (p < 0.01). Mean ground contact time differed in each of the side-hop, lateral COD and diagonal COD tests (143.5 ± 20.0 vs. 256.2 ± 66.1 vs. 320.4 ± 55.0). Contact times and test durations of side-hop, lateral COD and diagonal COD tests were shorter for older players (p < 0.01). Ground contact times of side-hop and change-of-direction manoeuvres are influenced by age, the type of sports and limb dominance. Such information is fundamental for future sports medicine research and needs to be considered in pre-season screening or when used as a criterion for return-to-competition of players with previous severe knee injury. Assessment of change-of-direction manoeuvres should be included in future return-to-competition test batteries. III.

Countermovement Jump and Isokinetic Dynamometry as Measures of Rehabilitation Status After Anterior Cruciate Ligament Reconstruction.

Despite an increase in the literature, few definitive guidelines are available to determine when an athlete has been fully rehabilitated after anterior cruciate ligament reconstruction (ACLR). To examine countermovement jump and isokinetic dynamometry measures to (1) identify which measures can best distinguish between ACLR and control participants and (2) provide normative values for identified measures in young adult male multidirectional field-sport athletes. Cross-sectional study. Orthopaedic hospital. Young adult male multidirectional field-sport athletes (n = 118) who had undergone unilateral patellar-tendon graft ACLR at least 6 months earlier and healthy male participants (n = 44) with no previous knee injury. Single-legged countermovement jump (SL CMJ). Three-dimensional biomechanical analysis of the SL CMJ and mean peak concentric knee-extension and -flexion torque using isokinetic dynamometry (ISO) were compared in the 2 groups. A stepwise logistic regression was carried out to identify the best predictors of ACLR- or control-group membership (SL CMJ height, limb symmetry index, peak power, joint power contribution, ISO peak torque, limb symmetry index variables). The control group differed strongly from the ACLR group in isokinetic knee-extension peak torque (d = -1.33), SL CMJ performance (d > 0.4), and limb symmetry measures in both ISO and jump outcomes (d > 1.1). The combination of measures from both ISO and SL CMJ identified group membership with an accuracy of 89%. Rehabilitation of ACLR patients may be complete when they achieve isokinetic knee-extension peak torque of 260% (±40%) body mass, SL CMJ performance of >17 cm (±4 cm), and reach-limb symmetry measures of >90% in both strength and jump outcomes. The outcomes in the control group can inform return-to-play criteria for young adult male multidirectional field-sport athletes after ACLR.

An experimental study on knee osteoarthritis patients

The prevalence of knee osteoarthritis is much lower in Asians or in black people. Few population-based studies regarding the incidence of knee osteoarthritis were found, with the incidence of knee osteoarthritis being higher in different age group. However, strict comparisons among these studies are limited, because the definition of the incidence of knee osteoarthritis is not the same for each study. A few risk factors for knee osteoarthritis were established, such as female gender and obesity. Also several cross sectional studies have found that the presence of a previous knee injury is significantly associated with the incidence of knee osteoarthritis. One of the limitations in previous studies is the definition of knee osteoarthritis. The most popular grading system for knee osteoarthritis is Kellgren–Lawrence classification. The data for the study was undertaken to determine osteoarthritis among the population in Chennai, Tamil Nadu, India. Frequencies and percentages were calculated to find the prevalence of osteoarthritis. For the purpose of the study a total of 207 female subjects aged (30-80) were engaged. The present study reports that the knee osteoarthritis among the sedentary women of the subjects were found to have a significant level (p

Association of daily walking with the risk of total knee replacement over 5 years: an observational study

Purpose: The presence of functional limitation, such as difficulty getting up from a chair or out of bed, is a reason adults elect for a total knee replacement (TKR), the definitive treatment for end-stage knee osteoarthritis (OA). Regular participation in physical activity, such as walking ≥6000 steps/day, reduces the risk of functional limitation in people with knee OA. However, it is not known whether walking more and in particular walking ≥6000 steps/day are associated with less risk of TKR. Moreover, given that functional limitation is more common in older (≥65 years) versus younger (<65 years) adults, it is not known whether the association of daily walking with TKR may be different for older versus younger adults. Therefore, the purpose of our study was to determine the association of daily walking and risk of TKR over 5 years. We also separately investigated this association in older and younger adults with or at high risk of knee OA to identify to whom daily walking may be most important for reducing the risk of TKR. Methods: Using data from the Osteoarthritis Initiative (OAI), we included participants who did not have TKR at or before the 48-month follow-up visit, which we considered our study baseline. Physical activity was measured with an accelerometer (Actigraph GT1M) worn during waking hours over the right hip during the baseline and quantified as steps/day. Time to TKR was quantified in months from the baseline visit date to the date of TKR through the 108-month OAI follow-up visit, i.e., 5 years later. The date for TKR was confirmed through adjudicated medical records whenever it was available during the course of OAI study. Participants without TKR at the 5-year follow-up were censored. Death and loss to follow-up in those without a TKR were considered competing events to TKR when they occurred between baseline and the 5-year follow-up. Hazard ratios (HR) with 95% confidence intervals (CI) were calculated from the Fine and Gray sub-distribution hazard model to assess the strength of the association between daily walking and risk of TKR in presence of competing events while adjusting for potential confounders (baseline age, BMI, sex, race, education, comorbidities, frequent knee pain, previous knee injuries or surgeries, and radiographic OA status). Daily walking was quantified as a continuous (i.e., per 1000 steps/day) and a categorical (< or ≥6000 steps/day) exposure measure in separate models. To examine if the association for daily walking and risk of TKR may be different by age groups, we performed subgroup analyses stratified by older (≥65 years) and younger (<65 years) adults. Results: Of the 1816 participants without TKR at baseline and who wore the monitor for >4 days (age [mean ± sd] 65.0 ± 9.1 years, BMI [mean ± sd] 28.4 ± 4.8 kg/m2, 55% female), 108 (6%) participants had TKR over 5 years. There was no significant association between daily walking (i.e., either continuous or dichotomous measures) and risk of TKR over 5 years in the overall sample or in younger adults (table). However, older adults were 12% less likely to have TKR for each additional 1000 steps/day walked (adjusted HR 0.88, 95% CI [0.79–0.99]). Moreover, older adults who walked > 6000 steps/day were 52% less likely to have TKR (adjusted HR 0.48, 95% CI [0.26–0.89]) compared to people who walked <6000 steps/day (table). Conclusions: Taking more steps/day and particularly walking >6000 steps/day may moderately reduce the risk for TKR in older (>65 years), but not younger (<65 years) adults. Our findings highlight the potential benefit of walking for older adults with or at risk of knee OA. A moderate reduction in risk of TKR may be an added benefit of walking more for older adults with or at risk of knee OA.TableAssociation of daily walking with the risk of TKR over 5 years.Daily walkingAdjusted HR(95% CI)1Overall sample (N = 1816)Adults (age in years)Older adults (≥65 years) (N = 912)Younger adults (<65 years) (N = 902)Per 1000 Steps/day0.94 (0.86-1.02)0.88 (0.79-0.99)∗0.98 (0.85-1.14)<6000 steps/dayReferenceReferenceReference≥6000 steps/day0.71 (0.45-1.14)0.48 (0.26-0.89)∗1.00 (0.44-2.29)1Adjusted for baseline age, BMI, sex, race, education, comorbidities, frequent knee pain, previous knee injuries or surgeries, and radiographic OA status.∗Significant at P value < 0.05 Open table in a new tab 1Adjusted for baseline age, BMI, sex, race, education, comorbidities, frequent knee pain, previous knee injuries or surgeries, and radiographic OA status. ∗Significant at P value < 0.05

Knee confidence in youth and young adults at risk of post-traumatic osteoarthritis 3–10 years following intra-articular knee injury

ObjectivesTo examine differences in knee confidence between individuals with a history of youth sport-related knee injury and uninjured controls. DesignHistorical cohort study. MethodsParticipants include 100 individuals who sustained a youth sport-related intra-articular knee injury 3–10 years previously and 100 age-, sex- and sport-matched uninjured controls. Outcomes included: Knee confidence (Knee Osteoarthritis and Outcome Score); fat mass index (FMI; dual-energy X-ray absorptiometry); and weekly physical activity (modified Godin–Shephard Leisure Time Questionnaire). Mean within-pair differences (95% CI) were calculated for all outcomes. Unadjusted and adjusted (FMI and physical activity) conditional (matched-design) logistic regression (OR 95% CI) examined the association between injury history and knee confidence. ResultsMedian age of participants was 22 years (range 15–26) and median age at injury was 16 years (range 9–18). Forty-nine percent (95% CI; 39.0, 59.0) of previously injured participants were bothered by knee confidence, compared to 12% (5.5, 18.5) of uninjured participants. Although there was no between group difference in physical activity, injured participants had higher FMI compared to controls (within-pair difference; (95% CI): 1.05kg/m2; (0.53, 1.57)). Logistic regression revealed that injured participants had 5.0 (unadjusted OR; 95% CI; 2.4, 10.2) and 7.5 times (adjusted OR; 95% CI: 2.7, 21.1) greater odds of being bothered by knee confidence than controls. ConclusionsKnee confidence differs between individuals with a previous youth sport-related knee injury and healthy controls. Knee confidence may be an important consideration for evaluating osteoarthritis risk after knee injury and developing secondary prevention strategies.

Tool for osteoarthritis risk prediction (TOARP) over 8 years using baseline clinical data, X-ray, and MRI: Data from the osteoarthritis initiative.

Osteoarthritis (OA), a multifactorial disease causing joint degeneration, often leads to severe disability. The rising rates of disability highlight the need for implementing preventative measures at early stages of the disease, which would especially benefit subjects at high risk for OA development. To develop a risk prediction tool for moderate-severe OA (TOARP) over 8 years based on subject characteristics, knee radiographs, and MRI data at baseline using data from the Osteoarthritis Initiative (OAI). Retrospective. 641 subjects with no/mild radiographic OA (Kellgren-Lawrence [KL] 0-2) and no clinically significant symptoms (Western Ontario and McMaster Universities Arthritis Index [WOMAC] 0-1) were selected from the OAI. MR images were obtained using 3.0T. Compartment-specific cartilage and meniscus morphology and cartilage T2 were assessed. Baseline subject demographics, risk factors, KL score, cartilage WORMS score, presence of meniscus tear, and cartilage T2 were used to predict the development of moderate/severe OA (KL = 3-4 or WOMAC pain ≥5 or total knee replacement [TKR]) over 8 years. Best subsets variable selection followed by cross-validation were used to assess which combinations of variables best predict moderate/severe OA. Model 1 included KL score, previous knee injury in the last 12 months, age, gender, and BMI. Model 2 included all variables in Model 1 plus presence of cartilage defects in the lateral femur and patella, and presence of a meniscal tear. Model 3 included all variables in Models 1 and 2, plus cartilage T2 in the medial tibia and medial femur. Compared to Model 1 (cross-validated AUC = 0.67), Model 3 performed significantly better (AUC = 0.72, P = 0.04), while Model 2 showed a statistical trend (AUC = 0.71, P = 0.08). We established a risk calculator for the development of moderate/severe knee OA over 8 years that includes radiographic and MRI data. The inclusion of MRI-based morphological abnormalities and cartilage T2 significantly improved model performance. 2 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1517-1526.

Lateral femoral notch depth is not associated with increased rotatory instability in ACL-injured knees: a quantitative pivot shift analysis

A deep lateral femoral notch (LFN) on lateral radiographs is indicative of ACL injury. Prior studies have suggested that a deep LFN may also be a sign of persistent rotatory instability and a concomitant lateral meniscus tear. Therefore, the purpose of this study was to evaluate the relationship between LFN depth and both quantitative measures of rotatory knee instability and the incidence of lateral meniscus tears. It was hypothesized that greater LFN depth would be correlated with increased rotatory instability, quantified by lateral compartment translation and tibial acceleration during a quantitative pivot shift test, and incidence of lateral meniscus tears. ACL-injured patients enrolled in a prospective ACL registry from 2014 to 2016 were analyzed. To limit confounders, patients were only included if they had primary ACL tears, no concurrent ligamentous or bony injuries requiring operative treatment, and no previous knee injuries or surgeries to either knee. Eighty-four patients were included in the final analysis. A standardized quantitative pivot shift test was performed pre-operatively under anesthesia in both knees, and rotatory instability, specifically lateral compartment translation and tibial acceleration, was quantified using tablet image analysis software and accelerometer sensors. Standard lateral radiographs and sagittal magnetic resonance images (MRI) of the injured knee were evaluated for LFN depth. There were no significant correlations between LFN depth on either imaging modality and ipsilateral lateral compartment translation or tibial acceleration during a quantitative pivot shift test or side-to-side differences in these measurements. Patients with lateral meniscus tears were found to have significantly greater LFN depths than those without on conventional radiograph and MRI (1.0 vs. 0.6mm, p < 0.05; 1.2 vs. 0.8mm, p < 0.05, respectively). There was no correlation between lateral femoral notch depth on conventional radiographs or MRI and quantitative measures of rotatory instability. Concomitant lateral meniscus injury was associated with significantly greater LFN depth. Based on these findings, LFN depth should not be used as an indicator of excessive rotatory instability, but may be an indicator of lateral meniscus injury in ACL-injured patients. Prognostic level IV.

The Impact of Knee Injury History on Health-Related Quality of Life in Adolescent Athletes

Current evidence suggests that, despite returning to full participation, physically active adults with a previous knee injury experience lower health-related quality of life (HRQOL) than those with no knee injury history. It is unknown if this relationship is present in adolescent athletes. To determine the impact of knee injury history on HRQOL in adolescent athletes who were medically cleared for full participation. Cross-sectional. Athletic training clinics. A convenience sample of 183 adolescent athletes, who were medically cleared for full participation, were grouped by self-report of a previous knee injury: positive knee injury history (HIS; n = 36, age = 15.7 [1.4]y, height = 168.0 [11.9]cm, and weight = 71.8 [11.9]kg) and no knee injury history (NO-HIS; n = 147, age = 15.5 [1.4]y, height = 166.0 [10.5]cm, and weight = 67.6 [14.6]kg). Participants completed the Pediatric International Knee Documentation Committee form and Pediatric Quality of Life Inventory during their preparticipation examination. Generalized linear models were used to compare group differences for the total and subscale scores of the Pediatric International Knee Documentation Committee and Pediatric Quality of Life Inventory. Main effects of injury group indicated that the HIS group reported significantly lower scores than the NO-HIS group for the Pediatric International Knee Documentation Committee total score (P < .001; HIS = 79.2 [21.7], NO-HIS = 95.8 [8.6]) and for the Pediatric Quality of Life Inventory total (P = .001; HIS = 85.7 [10.9], NO-HIS = 90.9 [7.3]), physical functioning (P = .002; HIS = 86.7 [13.6], NO-HIS = 92.1 [8.2]), school functioning (P = .01; HIS = 80.6 [12.4], NO-HIS = 86.8 [12.2]), and social functioning (P = .01; HIS = 89.3 [12.4], NO-HIS = 94.6 [8.9]) scores. No group differences were reported for the emotional functioning subscale (P = .13; HIS = 85.7 [17.7], NO-HIS = 89.7 [13.1]). No interactions or main effects of sex were reported (P > .05). Our findings suggest that, despite returning to full sport participation, adolescent athletes with a previous knee injury generally experience lower HRQOL than their peers with no knee injury history, specifically for knee-specific HRQOL, physical functioning, school functioning, and social functioning. Our results are similar to previous findings reported in college athletes and military cadets.

Association between MRI-defined osteoarthritis, pain, function and strength 3–10 years following knee joint injury in youth sport

BackgroundYouth and young adults who participate in sport have an increased risk of knee injury and subsequent osteoarthritis. Improved understanding of the relationship between structural and clinical outcomes postinjury could...

Injury Pattern in Icelandic Elite Male Handball Players.

To examine the incidence, type, location, and severity of injuries in Icelandic elite male handball players and compare across factors like physical characteristics and playing position. Prospective cohort study. The latter part of the preseason and the competitive season of Icelandic male handball. Eleven handball teams (185 players) from the 2 highest divisions in Iceland participated in the study. Six teams (109 players) completed the study. Injuries were recorded by the players under supervision from their team physiotherapists or coaches. Coaches recorded training exposure, and match exposure was obtained from the Icelandic and European Handball Federations. The players directly recorded potential risk factors, such as age, height, weight, previous injuries, and player position. Injury incidence and injury location and number of injury days. Recorded time-loss injuries were 86, of which 53 (62%) were acute and 33 (38%) were due to overuse. The incidence of acute injuries was 15.0 injuries/1000 hours during games and 1.1 injuries/1000 hours during training sessions. No significant difference was found in injury incidence between teams, but number of injury days did differ between teams (P = 0.0006). Acute injuries were most common in knees (26%), ankles (19%), and feet/toes (17%), but overuse injuries occurred in low back/pelvic region (39%), shoulders (21%), and knees (21%). Previous knee injuries were the only potential risk factor found for knee injury. The results indicate a higher rate of overuse injuries in low back/pelvic region and shoulders than in comparable studies.

Reliability of a Squat Movement Competency Screen in Individuals With a Previous Knee Injury.

Movement screens are a common method of assessing movement efficiency either against a specific criterion of segments/joint(s) motion (segmental method) or a summary label of general quality of the whole movement (overall method). While not as commonly utilized within clinical practice as the segmental method, the overall method is less time consuming to perform and more reliable. The aim of this study was to assess the reliability of the "overall" method approach during a squat in individuals with a previous knee joint injury. Cross-sectional, clinical measurement. Two-dimensional video recordings of 5 squat trials were recorded for 16 participants with a history of a major knee joint injury(s) and were visually rated by 3 novice and 3 expert raters. Weighted quadratic Kappa was used to determine the intra- and inter-rater reliability of the squat movement competency screen. Good inter-rater reliability for the expert and novice groups was observed. Intra-rater reliability was very good between analysis sessions for 1 expert rater. The overall method is a reliable method that enables allied health professionals of different levels of clinical experience to utilize a framework to assess movement quality during a squat in patients with a previous knee joint injury.

Acoustical Emission Analysis by Unsupervised Graph Mining: A Novel Biomarker of Knee Health Status.

To study knee acoustical emission patterns in subjects with acute knee injury immediately following injury and several months after surgery and rehabilitation. We employed an unsupervised graph mining algorithm to visualize heterogeneity of the high-dimensional acoustical emission data, and then to derive a quantitative metric capturing this heterogeneity-the graph community factor (GCF). A total of 42 subjects participated in the studies. Measurements were taken once each from 33 healthy subjects with no known previous knee injury, and twice each from 9 subjects with unilateral knee injury: first, within seven days of the injury, and second, 4-6 months after surgery when the subjects were determined to start functional activities. Acoustical signals were processed to extract time and frequency domain features from multiple time windows of the recordings from both knees, and k-nearest neighbor graphs were then constructed based on these features. The GCF calculated from these graphs was found to be 18.5 ± 3.5 for healthy subjects, 24.8 ± 4.4 (p = 0.01) for recently injured, and 16.5 ± 4.7 (p = 0.01) at 4-6 months recovery from surgery. The objective GCF scores changes were consistent with a medical professional's subjective evaluations and subjective functional scores of knee recovery. Unsupervised graph mining to extract GCF from knee acoustical emissions provides a novel, objective, and quantitative biomarker of knee injury and recovery that can be incorporated with a wearable joint health system for use outside of clinical settings, and austere/under resourced conditions, to aid treatment/therapy.

Conservatively treated knee injury is associated with knee cartilage matrix degeneration measured with MRI-based T2 relaxation times: data from the osteoarthritis initiative.

To investigate the association of cartilage degeneration with previous knee injuries not undergoing surgery, determined by morphologic and quantitative 3-T magnetic resonance imaging (MRI). We performed a nested cross-sectional study of right knee MRIs from participants in the Osteoarthritis Initiative (OAI) aged 45-79 with baseline Kellgren-Lawrence score of 0-2. Cases were 142 right knees of patients with self-reported history of injury limiting the ability to walk for at least 2 days. Controls were 426 right knees without history of injury, frequency-matched to cases on age, BMI, gender, KL scores and race (1:3 ratio). Cases and controls were compared using covariate-adjusted linear regression analysis, with the outcomes of region-specific T2 mean, laminar analysis and heterogeneity measured by texture analysis to investigate early cartilage matrix abnormalities and the Whole-Organ Magnetic Resonance Imaging Score (WORMS) to investigate morphologic knee lesions. Compared to control subjects, we found significantly higher mean T2 values in the injury [lateral tibia (28.10ms vs. 29.11ms, p=0.001), medial tibia (29.70ms vs. 30.40ms, p=0.014) and global knee cartilage (32.73ms vs. 33.29ms, p=0.005)]. Injury subjects also had more heterogeneous cartilage as measured by GLCM texture contrast, variance and entropy (p<0.05 in 14 out of 18 texture parameters). WORMS gradings were not significantly different between the two groups (p>0.05). A history of knee injury not treated surgically is associated with higher and more heterogeneous T2 values, but not with morphologic knee abnormalities. Our findings suggest that significant, conservatively treated knee injuries are associated with permanent cartilage matrix abnormalities.